Preservative and contact coat for light-sensitive devices



Jan. 4, 1938. c-s. w. HEwlTT v 2,104,483

PRESERVATIE AND CONTACT COAT FOR LIGHT SENSITIVE DEVICES I Filed March 5, 1936 ATTOR EY Patented Jan. 4, 1938 -11151111511) STATES PATENT: OFFICE: f

Pacsnavarivs AND coN'rAc'r CoA'r ron.V A

ucar-SENSITIVE Daviess yGeorge W. Hewitt, Wilkinlbnrg, Pa., `ailsignor to Westinghouse Electric & Manufacturing Com- A pany, East Pittsburgh, Pa., a corporation of Pennsylvania 6 Claims.

- Figure l is a cross-sectional view through av light-sensitive cell having my preferredform or preservative coating thereon;

Fig. 2 is an enlarged detail view of the central portion of Fig. 1; l

Fig. 3 is a top view of a translucent organic sheet in a form especially adapted to be incorporated in the preservative coatingj and Fig. 4 is a-perspective view of powdered silicious material for incorporation in my preservative coating.

In many respects, this invention is an improvement in the copending application oi? E. D. Wilson for preservative and contact coatings for light-sensitive devices Serial No. 67,277, filed March 5, 1936.

My invention has particular application to the copper oxide type of light-sensitive device,\and Fig. 1 illustrates apreferred type ofv this device.

The cell has a base of copper Il having a layer ofV cuprous oxide Il integrally formed thereon. A translucent layer l2 of a noble metal, such as gold, silver, or platinum, is sputtered thereon with the barrier plane I3 therebetween composed of an ionized gas layer. The particular construction and method of manufacture of this type of device is more specically described in the copending applications of E. D. Wilson, namely. Serial No. 578,399, filed December 1, 1931; Serial No. 4,235, filed JanuaryV 31, 1935; and Serial Nc. 20,362, flied May 8, 1935.

On the noble metal surface is formed a resinous coating Il, preferably of the natural resin type.

are rosin. collophony, abietic acid, ester g'u'm, or glycerized rosin. I also prefer to incorporate in thisv resin coating a plasticizer, preferablyV of the wax or glycerine type. Those readily available are beeswax, parafiln, Japan wax. normal butyl phthalate, ethylene glycol or other glycol.Y These plasticizers can range from,2% to 25% of the 'I'he natural resinsv readilyy available for such use Application March 5. 1936, serial No. 67,278 i (c1. ias-a9) described in the aforesaid copending application of E. D. Wilson Serial No. 67,277 for the purpose of making electrical contact with the noble metal layer i2. A metal ring f6 presses down on the broad surface of the conducting portion of. this preservative coating.

A -diiculty with the above-described type of cell has been the eilect of' extreme temperatures .CilA

`upon the preservative coating'- of the cell. At

very high temperatures, the,preservative coating l0 will become sticky, and at lowrtemperatures, the

coating will tend to chip off aw'ay from the noble metal film. I increase the temperature range between the sticky stage at Warm temperatures and the chipping-0E stage at cold temperatures 15 by incorporating one or more materials into the resinous coating. One of these materials is a highly translucent material, such as powdered silicious material I8. Readily available material of this class may be mica, glass or quartz pow- 20 dered into granules orzfiakes. This powdered material may be anywhere from 1% to 20% of the resinous coating. This material toughens-the resinous coating and enables it to better withstand extremes of temperature. 25

Another substance that is also helpful in preventing cracks and chips is the incorporation of 'an organic nlm of material I'I into the resinous coating. This lm may have a cellulose base,

but I prefer to use a fibrous webbing or sheet 30` especially of the soft thin absorbent type. Wood pulp, cotton, glass wool or asbestos cotton are suitable. My preference is especially for the soft thin absorbent paper material used as cushion sheets for stencil Backing. 35

veniently 'locating the edge 'of the disc, although 40 these tabs are not necessary. If cloth is used. thev contact material can pass through the texture of the cloth.

In coating the copper oxide disc having its f noble metal layer I2, the natural resin and its 45 plasticizer, if that is incorporated 'also'. is mixed with the desired proportion of silicious material i8 illustrated iny Fig. 4. This mixedpowder is uniformly distributed over the entire surface of the disc. By means of a special masking' de- 50 vice, the granulated low-melting alloy is deposited in an annular area around the outer edge of the resinous layer. The cell is then placed on a h ot v plate. The resinous coatingv fuses. and the alloy melts down, sinking through the molten resin to make contact with the noble metal. 'Ihe ber sheet Il is now placed centrally on' the fused resinous coating and becomes integral with it. The annular ring lIIS can then be placed to make a broad electrical contact to the llow melting alloy. A closed circuit can then be made with the aware that many modifications thereof are possible. My -invention, therefore, is not to be restricteczll except insofar as is 'necessitated by the prior art. n

I claim as my invention:

1. In combination with a translucent metal film, a protective transparent coating therefor comprising a resin from the group consisting of rosin, collophony, abietic acid, ester gum or glycerized rosin, a plasticizer from the group` consisting'of beeswax, paraffin, Japan wax, normal butyl, phthalate, ethylene glycol or other glycol, and a translucent reinforcing material from the group consisting of mica, glass or quartz and a material from the group consisting of wood pulp, cotton, glass wool and asbestos cotton.

2. In combinationwith a translucent metal lm, a protective transparent coating therefor comprising a resin from the group consisting of rosin, collophony, abietic acid, ester gum or glycerized rosin, a plasticizer from the group consisting of beeswax, paraln, Japan wax, normal butyl phthalate, Vethylene glycol or other glycol, and a translucent reinforcing material from the group consisting of mica, glass and quartz.

3. -A photo-electric cell comprising copper having at least a portion of its surface oxidized, a translucent coat of metal covering said oxidized surface and a protective translucent coating therefor comprising a resin from the group con-` ysisting of rosin, collophony, abietic acid, ester gum or glycerized rosin, a plasticizer from the group consisting of beeswax, parain, Japan wax, normal butyl phthalate, ethylene glycol or other glycol, and .a translucent reinforcing material from the group consisting .of mica, glass or quartz and a material from the group consisting of wood pulp, cotton, glass wool and asbestos cotton. y

4. A photo-electric cell comprising copper having at least a portion of its`surface oxidized, a translucent coat of metal covering said oxidized surface and a protective translucent coating therefor comprising a resin from the group consisting of rosin, collophony, abietic acid, ester gum or glycerized rosin, a plasticizer from the group consisting of beeswax, paraflin, Japan wax, normal butyl phthalate, ethylene glycol or other glycol, and a translucent reinforcing material from the group consisting of mica, glass, quartz. 5. In combination with a translucent metal film, a protective transparent coating therefor comprising a resin from the group consisting of rosin, collophony,` abietic acid, ester gum or glycerized rosin, a plasticizer from the group consisting of beeswax, paraffin, Japan wax, normal butyl phthalate, ethylene glycol or other glycol, and a translucent reinforcing material from the group consisting of wood pulp, cotton, glass Wool and asbestos cotton.

6. A photo-electric cell comprisingv copper having at least a portion of its surface oxidized, a translucent coat of metal covering said oxidized surface and a protective translucent coating therefor comprising a resin from the group consisting of rosin, collophony, abietic acid, ester gum or glycerized rosin, a plasticizer from the group consisting of beeswax, parain,.Japan wax, normal butyl phthalate, ethylene glycol or other glycol, and a translucent reinforcing material from the group consisting of wood pulp, cotton, glass wool and asbestos cotton.

GEORGE W. HEWITT. 

